1990668443 has 2 divisors, whose sum is σ = 1990668444. Its totient is φ = 1990668442.

The previous prime is 1990668403. The next prime is 1990668457. The reversal of 1990668443 is 3448660991.

It is a strong prime.

It is an emirp because it is prime and its reverse (3448660991) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 1990668443 - 2²⁰ = 1989619867 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 1990668391 and 1990668400.

It is not a weakly prime, because it can be changed into another prime (1990668403) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 995334221 + 995334222.

It is an arithmetic number, because the mean of its divisors is an integer number (995334222).

Almost surely, 2^1990668443 is an apocalyptic number.

1990668443 is a deficient number, since it is larger than the sum of its proper divisors (1).

1990668443 is an equidigital number, since it uses as much as digits as its factorization.

1990668443 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 1119744, while the sum is 50.

The square root of 1990668443 is about 44616.9075911812. The cubic root of 1990668443 is about 1257.9584902511.

The spelling of 1990668443 in words is "one billion, nine hundred ninety million, six hundred sixty-eight thousand, four hundred forty-three".